2024-2026 Audi Q8 AC Cooling Output Insufficient TSB

Audi Technical Service Bulletin (TSB) 87 25 98 2064077/6, issued on January 23, 2025, addresses concerns regarding insufficient air conditioning cooling output and potential leaks in the air conditioning system evaporator for various 2024-2026 Audi models, including the Audi Q8. This bulletin supersedes TSB Group 87 number 24-81 dated July 27, 2024, providing updated information and procedures for diagnosing and repairing these issues. Owners experiencing an Audi Q8 AC leak or poor cooling should be aware of this service information.

Symptoms of Insufficient AC Cooling

Owners of affected Audi vehicles may notice one or both of the following conditions:

• "The air conditioning does not cool the interior."
• "The cooling output of the air conditioning system is insufficient."

Upon inspection, technicians often find that the refrigerant circuit is not filled with the required amount of refrigerant, indicating a leak. The evaporator of the air conditioning system is identified as a potential source for such leaks, though it is not easily accessible from outside the vehicle.

Diagnosis and Leak Detection

Diagnosing an evaporator leak requires specific procedures since the component is not directly accessible. Technicians utilize several methods to detect leaks:

• Electronic Leak Detector: An electronic leak detector can be used to check for refrigerant presence at the center vents. This involves setting the blower to the lowest level and directing air distribution to the dash panel vents. Figure 2 in the TSB illustrates this process.
• Leak Detection Additive: If a leak detection additive is introduced into the refrigerant circuit, its deposits may become visible on the condensation drain after the air conditioner has operated at high load for a sufficient period. These deposits can also be observed on the vehicle's underbody, as shown in Figures 3 and 4 of the bulletin.
• Forming Gas Leak Test: For refrigerant circuits using R134a, R1234yf, and R744, a leak test with forming gas (calibration gas) can be performed. Detailed instructions for this procedure and necessary tools are available in the training module ATP 611 05_2022, titled "SoST - Leak test on the refrigerant circuit R134a, R1234yf and R744 in the Audi Knowledge Tank (AKT)."

Important Warnings for Technicians

This TSB includes critical warnings that technicians must follow during diagnosis and repair:

• WARNING: "For vehicles with refrigerant R744 only the "Leak test with forming gas" method is allowed."
• NOTICE: "Should the evaporator for the Q5 be confirmed leaking by way of this diagnostic procedure and replacement of the evaporator is performed it is necessary to loosen and refasten the Relay and Fuse Carrier 3 -SR3- (shown in figure 5, position 1) in the course of the repair. During reassembly of the vehicle, it is critically important that this relay and fuse carrier is reinstalled in its correct original position. Failure to reinstall the Relay and Fuse Carrier 3 precisely will result in water intrusion and subsequent component damage."

Repair Procedure Summary

If a leak is confirmed in the evaporator, the primary repair involves replacing the evaporator. After the replacement, it is crucial to thoroughly check the entire refrigerant circuit for any additional leaks. Any further leaks must be addressed according to the instructions provided in the Workshop Manual. This repair addresses the root cause of the Audi Q8 AC leak and ensures proper cooling function.

Warranty Information

For warranty claims related to this issue, the Service Number is 8760 and the Damage Code is 0050. Specific labor operations include:

• Check evaporator: Labor operation 8760 0199, covering the time necessary for diagnosis.
• Remove and install evaporator: Labor operation 8760 19xx, which refers to the Standard Repair Time (SRT) for associated operations.
• GFF / Guided Functions: Labor operation 0150 0060, for time stated on the diagnostic protocol.

Warranty claims must adhere to the Audi Warranty Policies and Procedures Manual. If the vehicle is outside of any warranty, this Technical Service Bulletin is for informational purposes only. The claim comment for this TSB is "As per TSB 2064077/6."

NHTSA ID: 11013743